Recently, increasingly more silver halide photographic light-sensitive materials are used, which has resulted in the quantity of silver halide photographic light-sensitive material to be developed. This trend correspondingly requires more rapid developing process, in other words, an enhanced processing capacity per specific duration.
This trend is also witnessed in the field of X-ray photographic light-sensitive material, in particular, X-ray films for medical diagnosis. More specifically, increasing diagnostic procedures due to increasingly frequent regular medical examinations, as well as increased checkup items to ensure more accurate diagnosis are contributing to the increase in the X-ray photographs being processed.
At the same time, the diagnostic result should be notified to a case as soon as possible.
To summarize this, there are mounting demands for unconventionally rapid developing process to expedite the medical diagnosis. Additionally, there are need for the swift provision of photographs, for example, in the vasography or X-ray photography during a medical operation.
To fulfill the above requirements in medical field, it is necessary not only to automate diagnostic procedures (photographing, transporting and the like) but to process X-ray films more rapidly.
The super-rapid processing, however, often incurs disadvantages, such as (a) insufficient density or deterioration in sensitivity, contrast, and maximum density, (b) in sufficient fixing, (c) insufficient water rinsing of films, and (d) insufficient drying of films. The insufficient fixing or water rinsing can result in discoloration as a film is stored, and hence the deteriorated image quality.
One countermeasure to solve these problems is to reduce the amount of gelatin involved in the photographic material. The reduced amount of gelatin, however, readily causes disadvantages uneven coating, brush marks during coating process of silver halide photographic light-sensitive materials. Additionally, photographic films involving less gelatin more easily cause the so-called scratch-induced blackening, which is a phenomenon where an area subjected to scratching with another film or foreign material will show a higher density than other areas once the films are developed.
As mentioned previously, there are mounting needs for the super-rapid photographic processing, and, however, with various problems to be solved. Incidentally, according to this specification, the term "super-rapid processing" means the photographic processing whose total duration is within a range of 20 to 60 seconds; within this duration, the leading edge of film is introduced into an automatic developing unit, and transferred via a dveloping bath, interface portion, fixing bath, interface portion, water-rinsing bath, interface portion, then a drying portion, and the same edge is eventually ejected from the drying portion, wherein the duration equals a quotient in sec. obtained by dividing a line transportation rate in m/sec. by a total length of processing line in m. The reason for why the periods associated with the interface portions should be included is well known in the photographic art; even in the interface portions, a gelatin layer in the photographic material contains a processing solution employed in a preceeding process and, accordingly, the photographic treatment substantially proceeds.
In Japanese Patent Publication No. 47045/1976, there is disclosed the significance of amount of gelatin in relation to the rapid processing, wherein the total processing duration including the interface areas is 60 to 120 seconds. However, such a long duration fails to comply with the recent needs for super-rapid processing.
The current X-ray photography requires a high-precision photographic technique involving smaller exposure dose. This need in turn necessitates the development of a photographic material being capable of providing a high-precision image with a smaller X-ray dosage, in other words, a more sensitive photographic material.
There are diverse sensitizing methods available to enhence the sensitivity of silver halide with a specific average particle size. The reported methods are as follows a method to add a developing accelerator such as thioether to an emulsion; a method to supersensitize a spectrally sensitized silver halide emulsion, by using a relevant combination of dyes; a method for improving a chemical sensitizer. These methods, however, not always fulfill the requirements for a highly sensitive silver halide photographic light-sensitive material. In other words, when any of the above methods is used to allow maximum chemical sensitization, the highly sensitive silver halide photographic light-sensitive material tends to cause fogging in the course of storage.
In the field of medical X-ray photography, conventional regular type light-sensitive materials having sensitive wave range of 450 nm are increasingly replaced with ortho type light-sensitive materials whose sensitive range having been changed by ortho sensitization to a region of 540 to 550 nm. The ortho-sensitized materials have a wider range of sensitive wavelength as well as enhanced sensitivity. Accordingly, such materials reduce the X-ray dosage as well as unfavorable effects on human body. In this context, the dye sensitization is a useful sensitization means. However, the similar means still has unsolved problems; for example, a sufficient sensitivity is not achieved with a specific type of photographic emulsions to be used.